I replaced the screw drive sprocket coupler and the door goes half way and returns back.

If it's just off a little you can adjust the limits. If it's off alot you need to take the gear set back out and set the belt / chain / screw to the closed position. run the operator to the closed position and then install the gear set.

It is very easy to get these out of sync. The instructions tell you how to set this up. Be sure the operator is run to the closed limit switch. The belt should be at the closed position when these gears are installed. Verify that the door works well manually. Be sure the rope disconnect has been released to engage the operator (with the door closed).

Follow the instruction sheet line by line.

Good Luck

Steve

Make sure you put the black cup back on the end of the motor shaft and that it is pressed all the way on. Make sure the RPM sensor is plugged in. If neither of these are the issue, then you probably did not have the motor shaft pushed all the way back when you tightened the coupler after replacing the worm gear. Loosen that coupler up and from the front of the motor (opposite end in which the coupler is on) push the shaft back as far as it will go. Hold it there while you tighten the coupler back up and then try it.

Make sure you put the black cup back on the end of the motor shaft and that it is pressed all the way on. Make sure the RPM sensor is plugged in. If neither of these are the issue, then you probably did not have the motor shaft pushed all the way back when you tightened the coupler after replacing the worm gear. Loosen that coupler up and from the front of the motor (opposite end in which the coupler is on) push the shaft back as far as it will go. Hold it there while you tighten the coupler back up and then try it.

Here are some things to check.

Loosen the chain enough so that you can remove it from the sprocket above the motor unit. With the door closed run the motor until the sprocket turns clockwise and stops. With everything attached replace and tighten the chain. Some adjusting of the up and down limits will probably be required.

Make sure you put the black cup back on the end of the motor shaft and that it is pressed all the way on. Make sure the RPM sensor is plugged in. If neither of these are the issue, then you probably did not have the motor shaft pushed all the way back when you tightened the coupler after replacing the worm gear. Loosen that coupler up and from the front of the motor (opposite end in which the coupler is on) push the shaft back as far as it will go. Hold it there while you tighten the coupler back up and then try it.

There are two bolts just in front of the motor that holds the rail. Remove these and you can move the motor back enough to slide the coupler off.

Make sure you put the black cup back on the end of the motor shaft and that it is pressed all the way on. Make sure the RPM sensor is plugged in. If neither of these are the issue, then you probably did not have the motor shaft pushed all the way back when you tightened the coupler after replacing the worm gear. Loosen that coupler up and from the front of the motor (opposite end in which the coupler is on) push the shaft back as far as it will go. Hold it there while you tighten the coupler back up and then try it.

You should also loosen the chain enough that you can remove it from the sprocket above the motor. Now with the door closed and everything else attached run the motor until it runs clockwise and stops. Replace and tighten the chain. Some adjusting of the up and down limits will be required.

Make sure you put the black cup back onthe end of the motor shaft and that it is pressed all the way on.Make sure the RPM sensor is plugged in. If neither of these are theissue, then you probably did not have the motor shaft pushed all theway back when you tightened the coupler after replacing the wormgear. Loosen that coupler up and from the front of the motor(opposite end in which the coupler is on) push the shaft back as faras it will go. Hold it there while you tighten the coupler back upand then try it.

No need to worry. Just remove the cover plate and you can see how the sprocket comes off. Changing the front sprocket is a whole lot quicker and easier than doing the rear sprocket.

Fist, turn down the force settings to half. The force settings can damage the door when turned up that high.. Your problem is with the limit settings. This is the three white screws on the bottom with the cover off. You will have to take the bottom off the gear and sprocket assembly and place the limit in the position that the trolley is and adjust the other two screws accordingly.